Glass sheet forming systems conventionally include a furnace for heating glass sheets for forming, a forming station that cyclically receives the heated glass sheets from the furnace to provide the forming and a cooling station located downstream from the forming station to provide cooling that may be slow cooling for annealing, faster cooling for heat strengthening or rapid cooling for tempering. The most efficient operation of such glass sheet forming stations takes place with the least possible downtime between switching from one job to another. Such job switching was originally accomplished by changing one or more molds utilized to provide the glass sheet forming, but such mold switching changes require significant downtime, four to six hours or more, that necessarily increases the cost of each formed glass sheet produced. To reduce the downtime, a pair of forming stations that can be moved sideways along the length of the glass sheet forming system for use of one or the other have also more recently been utilized, which is more economical than having two systems because the cost of the forming stations relative to the cost of the furnaces and cooling stations is much less and reduces the downtime since any mold changing can be performed when another production job is being performed.
Prior art glass sheet forming systems are disclosed by: U.S. Pat. No. 6,543,255 Bennett et al. which discloses a roll bed having detachable drive wheel assemblies that permit a lower press ring of varying shapes to be utilized in the forming; and U.S. Pat. No. 6,513,348 Shetterly et al. which discloses cooling of a formed glass sheet after the forming, both of which patents are assigned to the assignee of the application and are hereby incorporated by reference.